基于我国规范与PIARC标准的公路隧道需风量分析

以某长大高速公路隧道为例,结合我国隧道通风设计规范JTJ026.1-1999与PIARC2007标准(世界道路协会),针对不同行车速度,不同车辆更新情况、不同排放标准组合形式以及是否考虑NOx等情况,对各个不同工况的需风量分别进行计算,并从需风量计算方法、机动车排放量和污染物设计浓度三个方面对隧道需风量差异进行分析。研究结果表明:我国设计规范与PIARC2007存在较大差距,为了适应当前及今后我国交通量及机动车排放特点的发展趋势,我国现行规范应在机动车排放量、污染物设计浓度限值等方面做出必要改进以达到合理确定隧道需风量的目的。     

An approach for analysing the potential for material efficiency improvement

Material efficiency improvement saves energy and reduces the consumption of primary resources and reduces the volume of waste. In this article an approach for analysing the potential for material efficiency improvement is proposed and discussed. In this approach the product functions performed by the materials and various improvement measures are taken into account. The potential for material saving and associated energy saving is assessed and evaluated economically. In this paper the approach is tested in an analysis of the potential for material efficiency improvement with respect to plastic packaging in the Netherlands. The technical reduction potential is found to be 34 ± 7% (157 ± 30 ktonne virgin plastics). Realization of this potential would improve the energy efficiency of the lifecycle of plastic packaging by 31% (10 PJ in 1988). From our study we conclude that our approach can indeed be used to investigate the potential for material efficiency improvement. However, a reliable technical and particularly an economical assessment of reduction measures cannot be made until more detailed data become available.     

攀钢烧结烟气脱硫技术研究

介绍了攀钢烧结烟气的特点，SO2的来源。根据国内外烟气脱硫技术现状， 提出了攀钢烧结烟气脱硫的技术要求。     

Understanding Trait‐Dependent Community Disassembly: Dung Beetles,Density Functions,and Forest Fragmentation

Abstract: Anthropogenic disturbances such as fragmentation are rapidly altering biodiversity, yet a lack of attention to species traits and abundance patterns has made the results of most studies difficult to generalize. We determined traits of extinction‐prone species and present a novel strategy for classifying species according to their population‐level response to a gradient of disturbance intensity. We examined the effects of forest fragmentation on dung beetle communities in an archipelago of 33 islands recently created by flooding in Venezuela. Species richness, density, and biomass all declined sharply with decreasing island area and increasing island isolation. Species richness was highly nested, indicating that local extinctions occurred nonrandomly. The most sensitive dung beetle species appeared to require at least 85 ha of forest, more than many large vertebrates. Extinction‐prone species were either large‐bodied, forest specialists, or uncommon. These explanatory variables were unrelated, suggesting at least 3 underlying causes of extirpation. Large species showed high wing loading (body mass/wing area) and a distinct flight strategy that may increase their area requirements. Although forest specificity made most species sensitive to fragmentation, a few persistent habitat generalists dispersed across the matrix. Density functions classified species into 4 response groups on the basis of their change in density with decreasing species richness. Sensitive and persistent species both declined with increasing fragmentation intensity, but persistent species occurred on more islands, which may be due to their higher baseline densities. Compensatory species increased in abundance following the initial loss of sensitive species, but rapidly declined with increasing fragmentation. Supertramp species (widespread habitat generalists) may be poor competitors but strong dispersers; their abundance peaked following the decline of the other 3 groups. Nevertheless, even the least sensitive species were extirpated or rare on the smallest and most isolated islands.     

A comparison of required coefficient of friction for both feet in level walking

The required coefficient of friction (RCOF) is one of the critical elements in determining whether a slip incident might occur. Most researchers, when measuring RCOF, do not differentiate between the two feet of the same participant under the same walking condition. Results from a recent study (Chang et al., 2010) indicated that the stochastic distributions of the RCOF of both feet were different in 76% of the cases. Using the previous data (Chang et al., 2010), this paper presents a comparison of the RCOF for both feet of 50 participants under four level walking conditions resulting from two footwear types and two walking speeds using a t-test, commonly used by safety professionals to compare two pools of data. The current results indicated that 78% of the RCOF data showed a statistically significant difference between the RCOF from two feet for the same participant under each walking condition. The results of the logistic regression analysis used to identify factors that contributed to the outcome of the t-test indicated that the walking speed was the only factor with a statistical significance (p = 0.044).     

浅丘河道生态需水量计算方法对比研究——以鄂北地区水河为例

适宜的生态需水量是保障河道生态系统健康的重要因素,合理地计算生态需水量对河道生态系统评估具有现实意义。以鄂北地区典型浅丘河道——水河为例,基于Qp法(不同频率最枯月平均值法)、频率曲线法、最小月平均流量法、Tennant法及生物习性法5种方法的生态流量计算结果,探讨了各方法计算结果的合理性与适用性。结果表明:由于上下游河道水文条件差异性,上游断面采用生物习性法能较好地拟合河道水文节律变化和水质波动;同理,下游断面采用频率曲线法更加匹配下游河道水文、水质情况。因此,在河道上、下游断面分别采用生物习性法、频率曲线法计算得到适宜生态需水量为0.21 m^3/s、2.02 m^3/s。     

西北地区种植业需水分析——以泾河流域为例

采用面积定额法估算泾河流域31个县的农作物需水量,从农作物需水结构着手,探讨农业用水存在的问题。结果表明,泾河流域农作物需水量总计740 543.20万m3,农作物需水占总需水量的比例较高,为41.58%。粮食作物需水定额较经济作物高;就具体作物而言,菜、瓜类、水稻、棉花等需水定额较高,向日葵、薯类、胡麻等较低。各县(区)单位面积需水量差异较大,平均值为4 583 m3.hm-2;泾阳县最高,为5 682 m3.hm-2,定边县最低,为4 022 m3.hm-2。由于事先设定大多数作物的需水定额不随县(区)的改变而改变,因此需水量与作物结构密切相关。农业用水浪费严重,使泾河流域农作物实际用水量远高于需水量的理论计算值。为此,提出合理利用泾河流域农业水土资源的4项对策:调整种植业结构;多角度实施农业节水;完善农业水土资源优化配置定量方法;退耕还林还草,发展生态林牧业。     

BS EN ISO 20345：2011《个体防护装备安全鞋》标准的解析和建议

本文通过对最新的BS EN ISO 20345：2011《个体防护装备安全鞋》标准的列表介绍和概括性分析,找出了新标准检测项目仍存在的遗留问题和未考虑到的缺陷以及需要界定的术语,并提出了今后标准的再修订意见。此再修订意见的给出,为推动今后与安全鞋标准BS EN ISO 20345：2011属于同一体系的我国GB 21148-2007《个体防护装备安全鞋》标准修订提供参考意见。     

松辽流域生态流量赤字及其成因

水资源的过度开发导致了水短缺和水生态退化,因此,提供适宜的生态流量对维护河流健康具有重要意义.以往研究聚焦断面尺度的生态流量及其保障程度,尚未有效剥离上游子流域的影响.本研究以松辽流域为研究对象,运用VMF法、Tessmann-adapted法和Smakhtin-adapted法3种水文学法核算二级水资源区生态流量及1...